The recent slide in the price of diesel — and the prospects of that trend to continue — have caused trucking’s interest in natural gas to wane some, according to a recent report. The adoption curve for natural gas, however, is still expected to reach 23 percent of units sold by 2025.

The national average price for a gallon of on-highway diesel fuel fell 1.6 cents in the week ended Nov. 17 to $3.661. The drop comes after a 5.4-cent rise in the week prior, which snapped an 18-week streak without a price increase.

The national average price for a gallon of on-highway diesel fell another 1.2 cents in the week ended Nov. 3 to $3.623, according to the Department of Energy’s weekly report, as the country’s diesel price remains at a near four-year low.

The national average price for a gallon of on-highway diesel fell 4.2 cents in the week ended Oct. 20 to $3.656, according to the Department of Energy’s weekly report, marking the 16th week in a row without an increase.

The country’s average price for a gallon of diesel fuel should continue to fall this year and next, according to the Department of Energy, who projects diesel to average $3.68 in the fourth quarter, $3.85 for the year and $3.80 next year.

Volvo announced this week it is placing on hold its plans to launch a compression-ignited liquefied natural gas engine in North America, saying it is adapting its plans to the pace of the alt fuel market in the U.S. and Canada.